Apparatus for dressing crude asbestos



K. A. oEs'rr-:RHELD 3,286,940

APPARATUS FOR DRESSING CRUDE ASBESTOS Nov. 22, 1966 Original Filed July 18, 1961 KarI A. Oesterheyld United States Patent O 3,286,940 APPARATUS FOR DRESSING CRUDE ASBESTOS Karl Adolf Oesterheld, Luthe, near Wunstorf, Hannover, Germany Original application July 18, 1961, Ser. No. 124,923, now Patent No. 3,170,834, dated Feb.A 23, 1965. Divided and this application Sept. 9, 1964, Ser. No. 413,665 Claims priority, application Germany, July 20, 1960, 7,532; May 10, 1961, 0 8,052; May 15, 1961,

3 Claims. (Cl. 241-259) This is a division of application Serial No. 124,923,

filed luly 18, 1961 and now Patent No. 3,170,834, issued `February 2-3, 1965.

Asbestos is a raw material occurring at relatively few places throughout the world and its quality differs considerably according to the district where it is to be found.

The main factor which determines the quality was hitherto the natural length of the libres bundler together in the raw state. The price of long-ibred asbestos material is many times'that paid for short-iibred Iasbestos material.

For producing articles from asbestos cement, namely pipes, plates and moulded bodies which must have the strength factors laid down by international standards (ISO 7077), one was hitherto dependent upon long-libred asbestos material; short-iibred asbestos material, such as for example material known internationally under the designa- `tion 6 and 7, can only be used as filling material if it is added in not -too large quantities by weight to high-grade long asbestos fibres.

examined it will be found that the asbestos libres still hang together in bundles. 'I'his fact, which considerably impairs the strength and unformity of the structure of the asbestos cement product, is due to insuliicient dressing of the crude asbestos material.

In .view of the above-mentioned knowledge, the technical problem arises of finding a way of dressing the asbestos material in a more satisfactory manner. It was not possible to carry out the dressing with more vigorously acting means than those hitherto used for the conventional method of dressing, because this would subject the asbestos libres to still greater danger of being damaged and destroyed than was the case with methods of dressing hitherto employed.

In ,developing this inventive idea the entire quantity of v cement required for making the -asbestos cement finished products can be added to the libre-liquid mixture already before the treatment of the libres. If, for example finely lground quartz or finely ground asbestos cement blende is added to the libre-liquid mixture when dressing crude asbestos, a considerable saving of cement (about 10% of Vthe quantity of cement required without these filling substances) is achieved. This has the effect on the one hand to lowering the cost of the finished products and on the ,other hand of considerably improving the elasticity of the finished products.

The idea of adding one or several admixtu-re substances to the libre-liquid mixture from the outset can be utilized with advantage yalso when adding pigmentsfor colouring the libre material. The libre material alreay thoroughly dyed in the dressing process results in a very uniform colouring in the finished products.

3,286,940 Patented Nov. 22, 1966 ICC When carrying out the method according to the invention apparatus of different kinds can be employed depending upon the -kind of crude -asbestos to be dressed. For opening up or breaking up crude asbestos with robust fibres between rigid working surfaces, a device comes into question, for example, in which in a conically housing with a rigid inner working surface a corresponding conical rigid working body with spiral'protrusions on a mechanically driven shaft is so arranged that between the inner working surface of the housing 4and the surface of the conical working body there is a narrow passage gap in the shape of -a hollow truncated cone.

By this arrangement .a particularly favourable dressing of the libre material is attained in that the libre-liquid mixture in the passage gap, which is preferably made adjustable in width, is first fed with slow peripheral speed which then becomes gradually greater between the closely adjacent rigid working surfaces of the conical housing and the conical working body, thereby undergoing thorough vorticity so that the fibres are subjected to torsional effect.

A continuous bending to and fro and vigorous rubbing of the fibres against the rigid working surfaces can, however, also be Iattained with ya particularly simple dressing apparatus which consists of a stationary pipeV coil preferably arranged With a vertically upright longitudinal axis and which can be suitably adapted in length, radius and free passage cross-section, and which is connected up t0 the delivery side of a feed pump the speed of rotation of which is adjustable. T|he special advantages of such a dressing apparatus are its constructional simplicity, as it has no rotating driven parts, the reliable operation resulting therefrom and the low rate of mechanical wear. The upright [arrangement of the pipe coil presents operation advantages Ias regards simple emptying and flushing out of the pipe coil.

For the gentle treatment of crude asbestos with delicate libres between rigid working elements and elastically yield- Vable ycounter pressure elements, an apparatus is suitable in which .a conical working body composed or having at least a surface layer of rubber or elastically compressible plastic substance is arranged on a shaft mechanically driven with variable speed of rotation and so mounted in a conical housing that its wall surface and the rigid inner working surface of the housing enclose a narrow passage gap in the shape of a hollow truncated cone.

At the same time a continuous to .and fro bending and vvigorous friction of the bundles of libres and of the libres spondingly conical working body with gradually increasing peripheral speed the further the fibre-liquid mixture approaches the end of the conical working body having the large base surfa. The fibre-liquid mixture is thoroughly whirled during this feeding movement and as a -result the libre bundles and the individual libres arerepeatedly bent to and fro in different directions and at the same time a torsioning of the libres is attained while carefully dressing the libre material, which is extremely favourable for opening up the libres.

An elastically compressible working body can with advantage be composed of Ia packet of annular disks of rubber or elastic material clamped on the shaft immediately in Icontact with each other. For working less sensitive fibres, however, an apparatus is also suitable in which the working body consists of a metal body or .a metallic hollow body with a coating of rubber or elastically compressible synthetic material.

In order to increase the frictional effect, the inner workingsurface of `the conical housing may be provided with To :ensure `reliable working -fof the dressing apparatusv .itzis.advisable=toscoordinatewith the conical-workingbody '.fixedfonthe "shifta'ble. sleeve, a .pressure 'spring which holds iit Vinprits .operative `=position so that -itcan'yield resiliently.

' If foreign bodies, such as ungroundaclinkenpieces of 'as- `bestos fblende, stones, pieces .of .ironor the .llike get into the .passage :gap .with -the "nbre-liquid mixture, the conical working body'willthenyield and .thepassage gaplbe-tem- .porarily widened 'so'that the .foreign body can pass through :the gap. Y

The ydevices .for 'adjusting vthe Vwidth of .the Vtruncated Y `conicalpassage :and for vtheresilient v.yielding of the VVconical-.working body can `.with yadvantage be .combined by the arrangement of 'two sleeves "on the shaft, one.of which "sleeves carries the conical .working lbody `and `the other isleevezisfinf-operative connection with Ythe hand adjusting -wheel,whereby1the las`t-mentioned sleeve lhas a r'ange fservingas supporting surfacefor a pressure spring,'which `:pushes lforward the conical working .body in-to iopera-tive position',` and .for guidingbolts fixed 4on' a plate holding :the `conical 'working v.body and welded `on the lshiftable fsleeve, said vbolts being provided withabutmentnuts onl xscrewthreads at'their vfreeends. Y

11n a :preferred embodiment of the invention'the fend of the shaftfcarryingthershiftable sleeve with the -conical Yworking body :is exposed and provided `with-a conical he'adpieceof hardened steel linthe .region of the point 'of the conical housing where the bre-liquidmixture.enters :the .passage gap. The exposed rarrangementvof the .end

` are forced between k.the .inner edge 'of the zhdle `of each Y is xed on vertical rails,.32 of a carrier frameland eproi Y 'ofitheshafticarrying rtherelastic=working body contributes -ontfthe Aone hand, lto, trouble-free working of `the `dressing -apparatus when foreign bodies accidentally get -into the truncated conical passage gap and, on the yotherzhand,

Y ifacilitates 'the assembly Aandcleaning of the dressing apparatus. The r'conical steel lheadpiece keeps excessively Tlarge foreign'bo'dies 'awayfrom the passage gapandthus protects the dressing apparatus'a'gainst ldamage swithoutk itself being -liable vto damage large .foreignlbodies t fifi-the crude asbestos material hasto be treated particun larly carefully in view lof .the delicacy of the individual --.bres, it'is advisable to .employ an apparatus in which 4a shaft-'rotatablyrmounted `inside a cylindrical housing and fconnectedtoanfadjustable drive,.is surroundedlby an elas-V :tically'yieldable lining-capableof-being inflated .with 'com- "pressedain-and/orby a packet of .annular disks, fin which -rigid annular disks with ,a "bore diameter which yis greater than the diameter of ithe shaft alternate with annular disks tof'elastically yieldable material, such as rubber, witha `bore .diameter which/tis* equal or approximately equal 1to fthe diameter ofthe shaft; lthe `apparatus is provided lwith :liquid `mixture fed to .one end `of the housing and the apres- 4 l due to the fact that, on the one hand, the liquid pressure producing the feed movement and, on the 'other -hand, a transverse force componentact on the rotating shaftp,

If the apparatus consistsl of two functional parts ar.

ranged one-behind the other, the libre bundles :already partly .loosenedsin the `first functional part areubjected to repeatedfriction or rubbing owing to rthe, fact thatthey rubber disk and the shaft, whereby the .fibres are bent,

y=in that, on entering the ifannular chambers bordered by the bores of the. rigidannularY disks, Cthe bres @turn upwards.-

To make 'the repeated bending of the l'fibres necessary for opening 11p/the1bresv in `aperfcctnaanner, particularly intensive, the .shaft can be lprovided withone `or more helically wound riat fribs ion the Asection.,clamped by the Velastically `yieldable counter pressure elements. The fobject of these ribs is not, however, to force'thebreliquid mixture through the apparatus; the feeding vmovement is effected, .as yhas Valreadyfbeen tmen-tioned,1-by Ithe `:inflowy The helically wound Yribs :sac-1 `tually serve 'for bendingthe .libresinto a second `plane as `they .pass between Ythe .shaft :and ;the elastically ffyieldable pressure inV ever-y case.

counter .pressure elements.

SeveralV apparatus suitable for Ycarrying out the method` of dressing raw asbestos according to thevinvention are Tillustrated by iway'lof examplelinithe accompanying drawing, in which:

The gure is a1vertica1 longitudinal section through the apparatus with elastic :workingelements and arrigid counter, pressure element.`

The ligure on the drawing v-shows Van upright V:inverted 'funnel-,shapedhousing .31 with Y lateral .brackets 33 v`vided with gdepressionsV jlcviextending round .fits `conical inner surface.y The upper endfofthe housings31 is Lpro- -vided vvwith a flange 34 :and .connected to ia ,pipe conduit 112through which the fibre-liquidnixture :sucked by ,fa

v'feed pump out :of a containeri is pressed from :above sin.`

the direction-of the :arrow lwith :adjustable :pressure `into 'the conical housing 31.i At fthe' other end :having `:the

greater diameter wtheV conical hoi1s'i11g-31zis iconnected Vby s 'flangesSS--and 36 torarcylindricalhousing 37 whichfforms a Vcollecting chamber "38 Vfurthe lnbre-liquidnnixtule, fefd through Vthe dressing apparatus. Therfbreliquid imixvture -is :led o'ff from vthe Vcollecting ,chamber @3.8 Ithrough 1 Y 4a lateral-,connecting piece39 of the h011sing,37to1afpipe t 'conduit extending from the connecting `piece :39, :either yregulating elements by which the pressure of xthe iibresure .exerted r-by the `elastically v.yieldalile lining can be yadapted ato eachother so that as -the shaft rotates the fibre-liquid mixture is forced betweenthe lining `and fthe shaft with the necessary friction 'eect and -the required bending intensity vof `the libres. Another possibility of .regulating can be attained by driving Ythe shaftf .the

Aapparatus .through .the -intermediary of variable .speed ear. g In ,passing `between the rotating shaft and ythe elastically yieldable lining the .bundles of libres are subjected to vigorous friction, adjustable in intensity, and .at the same ,time the libres 3are .bent continuously to and fro,

-already after it has passed only once through the .dressing apparatus or, lif the kindV of vfibre material :to be 'dressed makes it necessary, `after fit has passed twice or :several times throughlthe dressing apparatus. .For'thisipurpose .a two-way cock is fitted in f-the discharge '.conduitiinthe "manner described infconnection with the'diagram shown yin lFIG, 44, 'andit is possible to'adjust the lplugf'of thecock so that the libre-liquid mixture Yis either conductedsto 7a place for further treatmentordrying, or-is returnedinto i the circulation through the said container and .,theeed.` pump to again pass through-the dressing apparatus.

YThefree `or exposed upper-end of '1a .fshaft 'Illipasses through 'ashiftablelbearing sleeve 40in acentral aperture in the end Wa-ll vof the `housing part l37 4into the .two-:part housing 37, 31. The shaftrtl, driven byanaelectricrmotor ythrough a variable speed gear, is rotatable vrin two laxial pressure'bearings42 which are fixed by meansofbraekets 43 on the 'vertical `rails 32 of a carrier frame. SOn'th'e free end ofthe shaft 41 a sleeve 45 is-Islipped which 'lis `connected for rotation to the-shaft 41`by-1mean's'ofakey `44 and longitudinallysliiftble-onthis fsha'ft. llOnf'thcup-y per end ofthe sleeve 45 Vprojecting upwards beyond Ithe shaft '41 .a conical'wor-king body 27 Tis xedbetweentwo plates 46 and Y47. 'This working `bodyjconsists -o'f a plurality of annular disks 27a of rubber or velastic synthetic subs-tance, progressively -larger in diameter, threaded on thel upper end of the sleeve-45 and tightly `clamped with their end faces bearing one against the other.

The plate 46 arranged in front of the small base of the conical body 27' is held Vand covered by a conical headpiece 50 of hardened steel. The headpiece 50 is provided with a screw pin 51 which is screwed into the screw threaded bore of a metal piece 52 which is welded on the front end of the metal sleeve 45 and closes the sleeve at its front end. The larger plate 47 is welded on the sleeve 45. By vscrewing the headpiece 50 more or less tightly, it is possible to impart to the packet of disks 27a -the correct initial stress.

A plurality of bolts 53 extending parallel to the shaft 41 are iixed on the plate 47 :and provided at their free ends with screw threads which extend through bores 55 in a flange 54 rmly welded on the shiftable bearing sleeve 40. A strong helical pressure spring 56, placed under initial stress between the plate 47 and the ilange Y 54, tends to shift the sleeve 45 carrying the conical Ibody 27 as far forward `as abutment nuts 57 screwed on the screw-threaded ends of -the bolts 53 :and locked in a suitable manner, will allow.

The elastic conical Working body 27 is as a rule yieldably held within the housing 31 coaxial'ly thereto by means of the pressure spring 56 in such a position that between the rigid inner wall surface of the housing 31 and the elastic outer surface of the conical working body 27 there is a narrow cone-shaped passage gap 58. If foreign bodies for example larger pieces of asbestos blende or shale, stones, pieces of iron or the like, should enter the c0ne-shaped passage -gap -58 with the iibre-liquid mixture, the conical Working body 27 yields in that it is pushed back on the shaft with the sleeve 45, thereby compressing the helical spring 56, with the result that the passage gap 58 is widened temporarily to such an extent that the foreign bodies can pass therethrough.

To enable the Width of the passage gap 58 to be adjusted to suit the kind of the bre material to be treated, a handwheel 59 is provided which has a screw-threaded boss 60 which is screwed on rto a screw-threaded sect-ion 41a in the middle of the shaft 41. A flat ring 61 is screwed on to the end ,face of a part of the handwheel boss 60 extending over the rear end portion of the sleeve 40 and the inner edge of this ning engages in an annular groove 62 formed in the periphery of the sleeve 40. By turning the handwheel 59 in one Vdirection the sleeve 40 and the conical Working body 27 connected thereto by the pressure spring 56 Will be shifted nearer to the small 'base of the conical housing 31` so that the passage gap 58 becomes narrower, whereas by turning the handwheel 59 in the opposite direction the distance of the surface of the conical working body 27 from the inner wall of the conical housing 31 will be increased and the passage gap widened accordingly. The handwheel 59 is locked against unintentional turning when in its adjusted position by means of a counter nut 63.

A bellows 64 is rixed at .one end to the plate 47 and at the other end to the llange 54 and prevents the fibre-.liquid mixture entering the chamber 38 `through the passage gap 58 from reaching the helical spring 56 and thus eliminates failures of the spring which might otherwise occur through fibre material or hard foreign bodies getting between the Winding-s of the helical spring 56.

The dressing apparatus :according to the invention can be employed not only for opening up crude asbestos but also for dressing or preparing other natural or synthetic fibre materials.

-I claim:

1. Apparatus for dressing crude asbestos comprising a housing having an interior conical surface, a working body in said housing having a conical surface opposing said housing surface, means for journalling said working lbody for rotation in said housing, the conical surface of said working body being defined by a plurality of elastic members, said elastic members being coniined between axially spaced end plates, means for biasingly urging said end plates toward each other, and means for axially adjusting said housing :and said Working body relative to each other whereby the width of 1a passage dened Iby said surfaces can be adjusted in size.

2. The apparatus as defined in claim 1 wherein said elastic members are .annular in shape, said elastic members surround a sleeve, and means for rotating said sleeve whereby said working body is rotated relative to said housing.

3. The apparatus as defined in claim 1 wherein inlet means and outlet means are provided .for introducing asbestos material into and withdrawing `asbestos material from said passage respectively, and said working body has a metallic conical headpiece adjacent said inlet.

References Cited by the Examiner UNITED STATES PATENTS 333,369 12/18185 Wilkeson 241--259 X 1,301,637 4/1919 Bair 241--244 2,094,842 10/ 1937 Had'sel 241--274 2,173,975 9/1939 Lyons 241-256 X 2,302,227 11/1942 Kasser 241--260 X 2,653,770 9/ 1953 Vicci 241-245 X 2,674,163 4/ 1954 P-revost 241-256 2,876,958 3/ 1959 Edwards 241-25 6 2,921,749 1/ 1960 Brink 2-41-260 2,954,938 10/ 1960 Higer 241--260 3,157,367 11/1964 Rath 241-274 ROBERT C. RIORDON, Primary Examiner.

D. KELLY, Assistant Examiner. 

1. APPARATUS FOR DRESSING CRUDE ASBESTOS COMPRISING A HOUSING HAVING AN INTERIOR CONICAL SURFACE, A WORKING BODY IN SAID HOUSING HAVING A CONICAL SURFACE OPPOSING SAID HOUSING SURFACE, MEANS FOR JOURNALLING SAID WORKING BODY FOR ROTATION IN SAID HOUSING, THE CONICAL SURFACE OF SAID WORKING BODY BEING DEFINED BY A PLURALITY OF ELASTIC MEMBERS,SAID ELASTIC MEMBERS BEING CONFINED BETWEEN AXIALLY SPACED END PLATES, MEANS FOR BIASINGLY URGING SAID END PLATES TOWARD EACH OTHER, AND MEANS FOR AXIALLY ADJUSTING SAID HOUSING AND SAID WORKING BODY RELATIVE TO EACH OTHER WHEREBY THE WIDTH OF A PASSAGE DEFINED BY SAID SURFACES CAN BE ADJUSTED IN SIZE. 